• Authors:
    • Riffkin, P.
    • MacEwan, R.
    • Clough, A.
  • Source: Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. Symposium 4.2.1 Soil, energy and food security
  • Year: 2010
  • Summary: Dryland cropping in the high rainfall zone (HRZ) of southern Australia has the potential to produce high yields of cereals, canola and pulses. However, actual yields often fall well short of the estimated potential. A survey of grain growers in the HRZ was conducted to gain a greater understanding of the factors which may prevent growers from achieving potential yields. The survey was developed in consultation with growers, soil scientists and agronomists and distributed nationally through an industry magazine. The survey captured grower perceptions of soil and crop management using multiple choice questions and free comment sections. This paper documents the section of the survey pertaining to soils. In this survey, growers throughout the HRZ provided common responses regarding their use of some forms of tillage, trafficking, chemical soil amelioration techniques and physical soil engineering techniques. Different responses were evident depending upon region and farm size for issues such as the use of conventional tillage, raised beds and lime. The perceived success of various types of soil management options is also discussed. This information is valuable for those who wish to identify which regions or grower audiences should be targeted for research and extension in soil management.
  • Authors:
    • Chen, D.
    • Dixit, P.
  • Source: Computers and Electronics in Agriculture
  • Volume: 74
  • Issue: 2
  • Year: 2010
  • Summary: High levels of subsoil salinity limit the growth and yield of dryland cereals in the Victorian southern Mallee, Australia. Currently available crop simulation models of wheat production perform poorly in this region, presumably due to their inability to account for subsoil limitations, mainly salinity. The objective of this work was to modify a spatially referenced Water and Nitrogen Management Model (WNMM) to account for the spatial pattern of subsoil salinity, by adjusting crop water uptake, in order to explain the spatial variation in wheat yield in this area. Measurements of above-ground biomass and yield of wheat, and the profile of soil salinity (0-80 cm) were made at 40 locations across an 88 ha paddock (35.78°S, 142.98°E) in the Victorian southern Mallee. The S-shaped water stress response function for crop water uptake proposed by van Genuchten (1987) was explored to modify the WNMM by adjusting the water uptake due to salinity, which significantly improved yield simulation over the original WNMM. The improvement in the model's ability to simulate wheat yield indicates that the subsoil salinity limits crop performance in the area. The incorporation of a salinity function in spatial crop models offers potential for simulating yield across a landscape and thus practicing precision agriculture provided salinity impact is considered dynamically.
  • Authors:
    • Wallwork, H.
    • Tester, M.
    • Hassan, M.
    • Lott, G.
    • Verbyla, A. P.
    • Oldach, K.
    • Genc, Y.
    • McDonald, G. K.
  • Source: Theoretical and Applied Genetics
  • Volume: 121
  • Issue: 5
  • Year: 2010
  • Summary: Worldwide, dryland salinity is a major limitation to crop production. Breeding for salinity tolerance could be an effective way of improving yield and yield stability on saline-sodic soils of dryland agriculture. However, this requires a good understanding of inheritance of this quantitative trait. In the present study, a doubled-haploid bread wheat population (Berkut/Krichauff) was grown in supported hydroponics to identify quantitative trait loci (QTL) associated with salinity tolerance traits commonly reported in the literature (leaf symptoms, tiller number, seedling biomass, chlorophyll content, and shoot Na + and K + concentrations), understand the relationships amongst these traits, and determine their genetic value for marker-assisted selection. There was considerable segregation within the population for all traits measured. With a genetic map of 527 SSR-, DArT- and gene-based markers, a total of 40 QTL were detected for all seven traits. For the first time in a cereal species, a QTL interval for Na + exclusion ( wPt-3114-wmc170) was associated with an increase (10%) in seedling biomass. Of the five QTL identified for Na + exclusion, two were co-located with seedling biomass (2A and 6A). The 2A QTL appears to coincide with the previously reported Na + exclusion locus in durum wheat that hosts one active HKT1; 4 ( Nax1) and one inactive HKT1; 4 gene. Using these sequences as template for primer design enabled mapping of at least three HKT1; 4 genes onto chromosome 2AL in bread wheat, suggesting that bread wheat carries more HKT1; 4 gene family members than durum wheat. However, the combined effects of all Na + exclusion loci only accounted for 18% of the variation in seedling biomass under salinity stress indicating that there were other mechanisms of salinity tolerance operative at the seedling stage in this population. Na + and K + accumulation appear under separate genetic control. The molecular markers wmc170 (2A) and cfd080 (6A) are expected to facilitate breeding for salinity tolerance in bread wheat, the latter being associated with seedling vigour.
  • Authors:
    • McLaughlin, M. J.
    • McBeath, T. M.
    • Noack, S. R.
  • Source: Crop & Pasture Science
  • Volume: 61
  • Issue: 8
  • Year: 2010
  • Summary: Although not commonly used in dryland cropping systems to date, foliar phosphorus (P) fertilisation may allow a tactical response to prevailing seasonal climatic conditions, with the added benefit of reduced input costs at sowing. However, variable outcomes have been reported from field trials predominantly conducted in the USA, and to a lesser degree in Australia. The effectiveness of foliar P is dependent on soil P status, soil water status, crop type, fertiliser formulation and prevailing climatic conditions. This review argues that the potential of foliar P fertilisation in Australian dryland cereal cropping could be enhanced by altering formulations for enhanced leaf penetration using adjuvants, and by accurately assessing the responsiveness of sites before application. This review demonstrates that it is important to use appropriate techniques such as isotopic labelling, to measure the efficacy and mode of action of foliar formulations.
  • Authors:
    • Butterbach-Bahl, K.
    • Kiese, R.
    • Murphy, D. V.
    • Barton, L.
  • Source: GCB Bioenergy
  • Volume: 2
  • Issue: 1
  • Year: 2010
  • Summary: Understanding nitrous oxide (N2O) and methane (CH4) fluxes from agricultural soils in semi-arid climates is necessary to fully assess greenhouse gas emissions from bioenergy cropping systems, and to improve our knowledge of global terrestrial gaseous exchange. Canola is grown globally as a feedstock for biodiesel production, however, resulting soil greenhouse gas fluxes are rarely reported for semi-arid climates. We measured soil N2O and CH4 fluxes from a rain-fed canola crop in a semi-arid region of south-western Australia for 1 year on a subdaily basis. The site included N fertilized (75 kg N ha−1 yr−1) and nonfertilized plots. Daily N2O fluxes were low (−1.5 to 4.7 g N2O-N ha−1 day−1) and culminated in an annual loss of 128 g N2O-N ha−1 (standard error, 12 g N2O-N ha−1) from N fertilized soil and 80 g N2O-N ha−1 (standard error, 11 g N2O-N ha−1) from nonfertilized soil. Daily CH4 fluxes were also low (−10.3 to 11.9 g CH4-C ha−1 day−1), and did not differ with treatments, with an average annual net emission of 6.7 g CH4–C ha-1 (standard error, 20 g CH4-C ha-1). Greatest daily N2O fluxes occurred when the soil was fallow, and following a series of summer rainfall events. Summer rainfall increased soil water contents and available N, and occurred when soil temperatures were >25 °C, and when there was no active plant growth to compete with soil microorganisms for mineralized N; conditions known to promote N2O production. The proportion of N fertilizer emitted as N2O, after correction for emissions from the no N fertilizer treatment, was 0.06%; 17 times lower than IPCC default value for the application of synthetic N fertilizers to land (1.0%). Soil greenhouse gas fluxes from bioenergy crop production in semi-arid regions are likely to have less influence on the net global warming potential of biofuel production than in temperate climates.
  • Authors:
    • Biswas, W. K.
    • John, M. B.
    • Kelly, K.
    • Graham, J.
  • Source: Journal of Cleaner Production
  • Volume: 18
  • Issue: 14
  • Year: 2010
  • Authors:
    • Li, Y.
    • Kelly, K.
    • Eckard, R.
    • Chen, D.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 136
  • Issue: 3-4
  • Year: 2010
  • Authors:
    • Chen, D.
    • Suter, H. C.
    • Islam, A.
    • Edis, R.
  • Source: Soil Biology and Biochemistry
  • Volume: 42
  • Issue: 4
  • Year: 2010
  • Authors:
    • White, I.
    • Moody, P. W.
    • Denmead, O. T.
    • Macdonald, B. C. T.
    • Bryant, G.
    • Naylor, T.
    • Wilson, S.
    • Griffith, D. W. T.
    • Wang, W. J.
    • Salter, B.
  • Source: Agricultural and Forest Meteorology
  • Volume: 150
  • Issue: 5
  • Year: 2010
  • Authors:
    • Wang, W.
    • Schwenke, G.
    • Scheer, C.
    • Hely, S.
    • Rowlings, D.
    • Rochester, I.
    • Officer, S.
    • Kelly, K.
    • Graham, J.
    • Eckard, R.
    • Chen, D.
    • Barton, L.
    • Grace, P.
  • Source: Proceedings of the 19th World Congress of Soil Science
  • Year: 2010